Heating means for locks



Feb. 18, 1941. B. B. WEST, JR

HEATING MEANS FOR LOCKS Filed Dec. 31, 1957 Patented Feb. 18, 1941 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to locks, and has reference more particularly to heating means for looks that are subjected to freezing temperatures.

Locks exposed to the elements, especially those 5 used on automotive vehicles, as on the doors of the passenger, tire and tool compartments of such conveyances, frequently become stuck on account of the congealing of the lubricant therein or the freezing of moisture that has gained access 10 to the locking mechanism, as during rains, snows and washings, and it is with great difllculty and inconvenience that the locks are restored to operative condition. When the tumblers of a cylinder lock become stuck from either of the foregoing 15 causes it is almost impossible to insert the key; and when the key is forced to normal position within the key slot, the tumbler actuating springs are incapable of retracting the key released tumblers to unlocking position with the result 20 that the key is liable to be bent or broken within the lock if undue turning force is applied thereto. Heretofore the situation has been met by crude and makeshift methods of applying heat to the locks, as by holding burning matches under 25 them, pouring hot water over them, applying hot cloths, etc.

The fundamental purpose of my invention is to overcome these difficulties by providing efficient and dependable means associated with a 30 lock for heating the locking mechanism thereby to soften the lubricant or melt the ice obstructing the tumblers or other working parts or otherwise interfering with the action of the lock and thus quickly and conveniently restoring a frozen 35 or stuck lock to normal operating condition.

A more specific object of the invention is to incorporate electrical heating means in locks, desirably in very intimate heat exchanging relation to the locking mechanism, whereby with 40. the minimum current consumption the frozen or stuck locking mechanism may be liberated.

Another object of the invention is to provide a combined latch and lock in which the latch operating member or handle is capable of move- 45 ment without releasing the latch while "the lock-- is in locking condition, and to associate therewith electrical heating means and a make-andbreak device or switch for controlling the supply of current to said means, the same being actuated o toclose the circuit when the latch operating handle is moved under the aforesaid condition. The foregoing objects, with others that will appear as this description proceeds, are attained in the illustrative embodiment of the invention 55 shown in the accompanying drawing wherein Fig. 1 is a sectional plan view and Fig. 2 is a sectional side elevation of a combined latch and lock of a. kind used on automotive vehicles and incorporating the invention; Figs. 3 and 4 are transverse sections on the respective lines 3-3 5 and l4 of Figs. 1 and 2; Figs. 5 and 6 are sections on the lines a-a of Figs. 1 and 2, the respective views being taken as though looking in the direction of the arrows 5 and 6 that are associated with said lines, and Fig. 7 is a perspective 10 View of one of the electrical heating elements.

The casing of the latch (which latch may be of any approved type) is designated I, and it is installed in the usual way in the door 2. In Figs. 1 and 2 a fragment of the door is indicated in dotted lines except the outer panel 3 that is shown in section. The latch operating handle is designated 5, and the inner end of the cylindrical shank 6 thereof is inserted through a hole in the panel 3 beyond which it is reduced in diameter at I, providing an annular shoulder 8. Beyond the part 'I the shank is further reduced to provide a terminal portion 9 that has the usual operative connection with the latch bar l0 so that when the handle is rotated under normal operating conditions it will retract the latch bar and release the door. These latch features are no part of my invention and accordingly it is deemed unnecessary to specifically show and describe them. It may be explained, however, that in the type of latch shown the latch handle is held in place by a shouldered screw H that is inserted through an opening on the inside of the door and is threaded into a tapped hole in the inner end of the shank.

The handle has a bore 12 extending axially of its shank 6, the same being enlarged at its outer end to provide a chamber i3 that is counterbored at ll. A cylinder lock 55 occupies said chamber, the same having a circular enlargement at its outer end that is accommodated by the counterbore H. An extension is of the lock has a working fit in the bore i2 and terminates short of the inner end of the bore. An eccentric stud or crank pin i1 projects from the inner end of the extension l6 into a vertical slot 18 of a locking bolt l9 that is slidable in a transverse 1 opening in the part 1 of the shank. The base portion 20 of a keeper 21 is attached, as by rivets 22 (Fig. 3), to the front surface of the latch casing l, the body portion of the keeper being semi-cylindrical and embracing one side of the part I of the shank. The keeper is provided with a slot 23 for the reception of one end of the bolt l9, said slot being elongated in a vertical direction, as clearly shown in Fig. 3, in order to permit a limited movement of the operating handle in a counter-clockwise direction when the bolt is in locking condition. This limited movement of the handle is ineffective to release the latch.

The lock I5 is retained within the chamber l3 by a pin 25 that is projected through a hole in the part I of the shank tangent to and slightly intersecting the bore l2 and occupying an annular groove 2i of the lock extension Hi. The pin 25 also holds in place upon the reduced part i of the shank a disk 3. of insulating material, within the front face of which is inlaid a segmental contact member 3| (Fig. 6). Thus, the disk II is secured against rotation to the shank of the operating handle, and when the handle is turned in a counter-clockwise direction as previously explained it will cause one end of the contact member 3| to override and bear upon a contact member 32 (Fig. 5) that is set within the rear face of a disk 33 of insulating material that is shown as applied to the inner surface of the door panel 3 and held fixed with respect thereto by screws 34 that pass through holes in the panel and are threaded into an escutcheon 35 that surrounds the shank 6 outwardly of the panel. The contact members 3| and 32 constitute the make-and-break device or switch that controls the supply of current to the heating means of my invention, as will hereinafter more fully appear.

The tumblers 38 of the cylinder lock |5 are adapted to be projected into one or the other of diametrically opposed recesses 39 that are formed in the handle and open into, and extended longitudinally of, the chamber l3. Intermediate the recesses 35, and also opening into the chamber l3 and extending some distance beyond the inner end thereof, are other recesses or channels 41 within which are fitted heating elements designated generally by the reference numeral 43 and one of which is shown in perspective in Fig. 7. Each heating element comprises a body 44 of suitable heat conducting insulating material, desirably of the highly compressed, very hard, cementitious kind commonly used in electrical heating appliances, said body being segmental in cross section and encaslng an electrical resistor 45, a terminal whereof is exposed at 46 through the outer surface of the front end of the body 44, A lead wire 41 is connected to the opposite end of the electrical resistor and is insulated throughout the greater portion of its length. The insulated portions of the lead wires 41 are extended rearwardly through bores of the shank 6 that open through the shoulder 8 in register with holes in the disk 30 through which the ends of the wires are extended. Rearwardly of the disk 30 the terminals of said wires have electrical connection with the contact member 3|, desirably through rivets 50 that hold said member in place and to the inner ends of which the wires are soldered. Current is conducted from a suitable aom'ce, as from the battery of the vehicle, to the contact member 32, by a conductor 5| that is shown as having its end soldered to a rivet 52 by which the contact member 32 is fastened to the disk 33.

In case a thin film of lubricant on the tumblers 33 of the lock l5 congeals from exposure to low temperatures sufliciently to obstruct movement of the tumblers; or moisture within and about the locking mechanism freezes and prevents normal operation thereof, the handle 5 may be turned in a counter-clockwise direction to engage the contact member 3| with the contact member 32 thereby to permit current to flow from the source (not shown) through the wire 5|, contact members 32 and 3|, lead wires 41 and resistors 45 to where the circuit is grounded through the terminals 46 of the resistors that are in contact with the metal handle. As long as the handle is held in a position to maintain the contact members in engagement with each other, current will flow through the resistors 45 and 9,: they become heated their elevated temperatun is transmitted to the locking mechanism thereby to soften the lubricant or melt the ice and release the tumblers so that they will respond in a normal way to the insertion of the key which serves to retract the tumblers from the recess 39 and permit the lock cylinder, with its extension l6, to be rotated by means of the key through 180 or until the tumblers are in register with the other recess 39. The rotation of the lock is limited to 180 by a pin 55 that projects from the wall of the recess i3 radially into a segmental notch 56 in the rear end of the lock cylinder. When the lock is thus rotated the eccentric stud or crank pin II shifts the bolt I9 to its unlocking position in which it is withdrawn from the slot 23 of the keeper 2|. With the operating handle thus released, it may be given a normal (tiurn to retract the latch bar l0 and release the Although I have shown and specifically described my invention as incorporated in a cylinder lock associated with a vehicle door latch of a certain type, it is to be understood that this is by way of illustration only and that the invention is applicable to locks of different kinds and environments. For example, the invention has marked utility in connection with boxes that enclose out-of-door telephones, as police and taxicab call boxes, etc.

Also, any approved type of heating element may be substituted forthe embedded kind hereinbefore described, according to the nature and requirements of the construction at hand.

Further, in the broader aspect of the invention, what is herein shown as the latch handle may be regarded the lock housing; the invention being susceptible to all forms and variations falling within the scope of the appended claims, and where the term "latch bolt" is used in the claims it is intended to cover any equivalent holding means or element.

Having thus described my invention, what I claim is:

1. In combination, a housing having a cylinder chamber and opposed recesses opening into the same and extending longitudinally thereof, a cylinder lock plug having tumblers and rotatable in the chamber, the tumblers whereof cooperate with said recesses, the housing being provided with channels intermediate said recesses, electrical heating elements occupying said channels, an electric circuit including said heating elements,

a switch in said circuit, and a locking element having operative connection with the lock plug.

2. In combination, a housing having a cylinder chamber and abutments spaced apart circumferentially thereof, a cylinder lock plug having tumblers and rotatable in the chamber, the tumblers whereof cooperate with said abutments, the housing being provided with a cavity adjacent said chamber, an electrical heating element occupying said cavity, an electric circuit including said heating element, a switch in said circuit, and a locking member having operative connection with the lock plug.

3. In combination with a latch including, a latch bolt and a movable operating member, locking mechanism governing the actuation of the latch bolt by said member, electrical heating means comprising an electrical resistance element and a mass of heat conducting electrical insulating material surrounding the same for heating the locking mechanism, the same being in such relation to said mechanism as to melt a foreign substance congealed thereon whose solidified condition interferes with the operation of the mechanism an electric circuit including said, heating means, and a make-and-break device in the circuit actuated by the latch bolt operating member, said member being capable of limited movement without effecting release of the latch bolt while the locking mechanism is in looking condition.

4. In combination with a latch including a latch bolt and a rotatable operating member therefoaa keeper with respect to which said member is movable, a locking bolt carried by the memher for locking engagement with the keeper, the locking bolt and keeper being so constructed and related that the member is capable of limited rotative movement in a direction opposite that in which it is moved for the purpose of retracting the bolt and while the locking bolt is in efl'ective position, a lock cylinder rotatably sustained by the operating member and having operative connection with said locking bolt, electrical heating means comprising an electrical resistance element and a mass of heat conducting electrical insulating material surrounding the same and arranged in heating relation to the lock cylinder, an electric circuit including the electrical heating means, a switch in said circuit comprising a contact carried by and movable with the latch bolt operating member, and a second contact wherewith said member has relative movement, the contacts being adapted to be engaged during the aforesaid limited movement the latch bolt operating member.

5. In combination with a movable member, an instrumentality adapted to be actuated thereby when moved in one direction, locking mecha- 5 nism governing the actuation of said instrumentality by said member, electrical heating means comprising an electrical resistance element and a mass of heat conducting electrical insulating material surrounding the same for heating the locking mechanism, an electric circuit including said heating means, and a make-andbreak device in the circuit actuated by movement of said member, the member being capable of movement in a direction opposite to that aforesaid to actuate said device while said mechanism is in looking condition.

6. In combination with a latch including a latch bolt and a tubular rotatable latch bolt operating handle, a cylinder lock plug having tumblers and rotatable within the bore of the latch bolt operating handle, the same governing the actuation of the latch bolt by the handle, the handle having abutments wherewith the tumblers of the cylinder lock plug cooperate, an electric heating means comprising an electrical resistance element and a mass of heat conducting electrical insulating material surrounding the same, said heating means being housed within the handle in such relation to the lock plug as to melt a foreign substance congealed in or upon the same, a contact member movable with the latch bolt operating handle and having electrical connection with the heating means, a second contact member with respect to which the latch bolt 35 operating handle is rotatable and wherewith the first mentioned contact member is adapted to be engaged when the handle is rotated while the lock plug is in condition to prevent actuation of the latch bolt, and an electric circuit including said 40 contact members and the heating means.

BRENNAN B. WEST, J R. 

